Fluorinated cotelomers based on vinylidene fluoride (VDF) and hexafluoropropene (HFP): Synthesis, dehydrofluorination and grafting by amine containing an aromatic ring

The synthesis of C₆F₁₃CH₂C(CFCFCF₃)N-C₂H₄-C₆H₅ (11) from the addition of H₂N-C₂H₄-C₆H₅ onto C₆F₁₃CH₂CF₂CF₂CFHCF₃ (3) is presented. C₆F₁₃CH₂CF₂CF₂CFHCF₃ (3) and C₆F₁₃CH₂CF₂CF(CF₃)CF₂H (3′) isomers were obtained from the thermal stepwise cotelomerization of vinylidene fluoride and hexafluoropropene with C₆F₁₃I, followed by the selective reduction of the iodine end atom. At 200 °C, the 3/3′ molar ratio reached 9.0. In contrast to selective reduction, dehydrofluorination led to various derivatives, which were characterized by ¹H NMR and ¹⁹F NMR spectroscopy, and hence a reaction pathway could be suggested. The grafting of an amine containing an aromatic ring onto the cotelomers based on VDF and HFP occurred selectively on VDF/HFP diad and, in some instances a further step involving the formation of an imine was observed. The addition of 2-phenylethylamine onto the dehydrofluorinated intermediates was found to be quantitative.